Introduction of single-phase variable frequency drive

Single-phase variable frequency drive belongs to a category of variable frequency drive products. Compared with other components, the obvious difference is that the working principle is different, and the later operation experience is also quite different. Therefore, friends who are interested in purchasing need to refer to the actual specific needs to start analysis and learn from, to help determine a feasible product plan. So what I will introduce to you today is a detailed and professional introduction to the wiring and principles of single-phase variable frequency drives. Interested friends can start to understand and analyze them in detail.

1. Working principle of single-phase variable frequency drive

The single-phase capacitor running motor has main winding and auxiliary winding (starting winding) on the winding, and the winding voltage is usually single-phase AC 220V. In theory, the operation of the single-phase capacitor operation motor must provide two-phase AC voltage. Since there is no real two-phase power supply system, in practical applications, phase-shift capacitors are used to start the operation. The adjustment and control of the number of revolutions of the single-phase capacitor running motor is more troublesome. It is necessary to add a tachometer motor winding to the motor, and measure the winding voltage, which is realized by the control device. The structure is complex, the cost is increased, and the speed regulation performance is not ideal. Single-phase capacitor running motors with tachometer motors are also more expensive than ordinary single-phase capacitor running motors. At present, the variable frequency drive of three-phase power supply has matured in theory and commercialization in the market. It has been widely used. However, the variable frequency drive corresponding to the "two-phase motor" with single-phase power input is blank. There is no corresponding product to provide and apply.

2. Single-phase variable frequency drive wiring

Single-phase 220v variable frequency drives cannot be connected to single-phase motors.

In this case, the variable frequency drive will judge it as a motor failure. If the variable frequency drive has the function of shielding phase loss protection and output voltage setting function, it can be used. However, the variable frequency drive capacity needs to be checked according to the output current. If the variable frequency drive does not have the above functions, the protection of the variable frequency drive will start and stop the output. Single phase cannot be accepted.

Another reason for not recommending is: if the single-phase motor is capacitively phase-shifted, the frequency changes, and the requirements for the capacitance capacity will also change.

A frequency converter is generally a power control device that converts a power frequency power supply into another frequency by using the on-off function of a power semiconductor device. The main circuit of the frequency converter can be roughly divided into two categories: the voltage type is the frequency converter that converts the DC of the voltage source into the AC, the filter of the DC circuit is the capacitor; the current type is the frequency converter that converts the DC of the current source to the AC, Its DC loop filter is an inductor.

Single-phase motors generally refer to low-power single-phase asynchronous motors powered by single-phase AC power (AC220V). This type of motor usually has two-phase windings on the stator, and the rotor is a common squirrel cage type. The distribution of the two-phase windings on the stator and the different power supply conditions can produce different starting and operating characteristics.

There is a lot of knowledge introduced to you above, including the working principle of single-phase variable frequency drive and the analysis and introduction of the connection angle. From this, we can know that there are many contents with reference value, which are also very helpful for purchase or actual use and operation experience. And the requirements of single-phase variable frequency drives for other related similar components are also mentioned above. After all, there are many factors that determine the final advantage experience of a product, and only comprehensive results can achieve satisfactory results.